The core of EnneaHost is only around 100 lines. It and the optional components are very trivial. Easy to understand, and easy to adapt to your needs. None of them do very much, but together the whole is greater than the sum of the parts.
EnneaHost is built out of several third-party components and several first-party ones. All are independently useful outside of EnneaHost.
Uses stable Docker containers as its base rather than over-relying on deployment systems such as Ansible or Chef, which tend to bit-rot quite quickly. It provides a Heroku style deployment system (git push your repository to build it), but that's optional and secondary. Build your containers today and they will still work 5 years from now.
Right now the PaaS space is very dynamic: Deis, Flynn, Octohost and Dokku are just some of the open source contenders, and there are several other closed source systems. Yet none of these are built on new exciting technologies such as Kubernetes and Mesos. None of them are very mature.
EnneaHost assumes that it isn't going to "win". Instead it seeks to make your transition costs very minimal. We just assume that both Docker and Consul are going to "win", and use those two components to do most of the heavy lifting. We also attempt to use these two components in a fashion that makes moving away from EnneaHost really simple.
We've tried to keep the EnneaHost metadata in a form that makes it
useful for documentation on how to run the components without
EnneaHost. For example, if you distribute a Dockerfile, the
DOCKER_RUN_OPTIONS line should be immediately useful to somebody who
is running the container manually, even if they don't know what
EnneaHost is.
EnneaHost will deploy and work on a single host. However if you have multiple hosts, EnneaHost will provide redundancy and load balancing.
tutum buildstep uses Heroku build packs to support tons of different languages and frameworks.
Not only web applications are supported. Virtually anything that can be put into a Docker container can be run by EnneaHost.
Ennea is the ancient Greek prefix for ninth, in the same way that octo is the prefix for eighth. EnneaHost was heavily inspired by OctoHost. I do hope that OctoHost liberally steals back from EnneaHost.
There are two ways to start a container on Enneahost: directly or via git push.
Store an empty JSON object "{}" in the consul key "enneahost/images/". Enneahost will then automatically run the named Docker image.
Optional attributes that may be set in the JSON object:
-
namespace: default "registry.service.consul:5000". The Docker namespace. This is either the location of a private Docker repository, or a prefix on the Docker Hub. Use "library" to pull official Docker images.
-
tag: default "latest".
-
run_options: default "". These are the options that are passed to Docker. Do not use "-d" or similar options. These options are sent through consul-template to allow dynamic customization. Consul-template will automatically restart your container if any dynamic configuration changes.
-
run_cmd: default "". The options that are passed to the executable inside the Docker container. These also support consul-template customization.
Make sure your repository contains a Dockerfile. Push your repository to the master branch on your EnneaHost. The repository will be automatically built, pushed to a repository and started.
git remote add enneahost git@<ip>:<name>
git push enneahost <branch>:master
You may set the environment variables "DOCKER_RUN_OPTIONS" and "DOCKER_RUN_CMD" in your Dockerfile to customize. See above for details.
The current version of Enneahost uses Upstart and has only been tested on Ubuntu 14.04.
Make sure you have vagrant and ansible installed on your development machine. Unfortunately, ansible is not available for Windows. If there is demand, I can modify the Vagrantfile so that ansible is run from within the vagrant box rather than outside.
git submodule init
git submodule update
vagrant up
After your vagrant image has been provisioned, follow the instructions printed by vagrant to install your SSH keys.
TBD.
See INSTALL.md
required:
recommended:
installed by the ansible script, but not used:
This is the core of EnneaHost. It starts docker containers when a key is added to enneahost/images/ in consul.
webapp-nginx (optional)
Creates a load-balancing nginx proxy configuration for a webapp
ennea <name> run <cmd...>: run cmd in new container (docker run)ennea <name> exec <cmd...>: run cmd in existing container (docker exec)
git builder (optional)
Builds and pushes docker images on a git push
progrium/registrator (optional)
Registers docker services in Consul automatically.
docker-plugin-kv-consul (optional)
Automatically sets consul keys on container start based on values in the Docker container environment.
Set the consul key enneahost/images/postgres to
{
"namespace": "library",
"run_options": "-p 5432:5432"
}
For production use we highly recommend the use of --volume=<path>:/var/lib/postgresql/data to make it harder to accidentally trash all your databases.
For the sake of simplicity we're going to use a Heroku buildpack to Dockerize our Rails application. This is an easy, but heavy, solution.
Dockerfile:
FROM tutum/buildstep
RUN /start assets
EXPOSE 80
ENV PORT 80
CMD ["/start", "web"]
VOLUME /app/public
ENV KV_SET:webapp/#<IMAGE_NAME># foo
ENV KV_SET:#<IMAGE_NAME>#/cname example.com
ENV KV_SET:#<IMAGE_NAME>#/public #jq<.Volumes["/app/public"]>#
ENV DOCKER_RUN_OPTIONS -P --env=DATABASE_URL=postgres://[email protected]/mydb-production
The funny #<IMAGE_NAME># syntax takes advantage of kv-consul to dynamically insert the actual image name. This is usually extraneous: I would recommend just replacing #<IMAGE_NAME># with your application name to keep things clear. Just make sure you use the same name when pushing to enneahost.
The KV_SET:webapp line triggers the ennea webapp plugin. The cname and public lines are parameters for the plugin.
Push your app to enneahost:
git remote add enneahost git@<ip>:<name>
git push enneahost master
Give it a few minutes to build the image and push to the repository. After it has been pushed to the repository your git push command will return. Then give it a few more minutes for EnneaHost to download the image from the repository and for your Rails app to start running.
You then should be able to initialize your database:
ennea <name> run rake db:create
ennea <name> run rake db:migrate
ennea <name> run rake db:seed
Your application should now be running on your host and should be available at the cname you provided as well as <name>.<ip>.xip.io.
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